The present invention relates generally to assemblies for the interconnection of high frequency switching power semiconductor devices and deals more specifically with an assembly for providing low impedance interconnection between high frequency switching power semiconductor devices and a low inductance modular capacitor to minimize the development of high voltage transient spikes across the semiconductor devices during rapid turn-on/turn-off switching. The present invention also relates to a low inductance modular capacitor for use with the interconnection assembly.
High power switching applications such as those found in high power multi-phase DC-to-AC converters which generate multi-phase AC voltages for powering multi-phase motors and the like are generally limited in performance due to limitation in switching high DC currents at high frequencies to produce a desired AC voltage signal output with a desired magnitude and harmonic content. Often, the switching power semiconductor devices are subjected to voltage transient spikes during switching which, without suppression, destroy the semiconductor device. There are a number of known techniques for reducing the development of high voltage transient spikes on high frequency switching power semiconductor devices during rapid turn-on/turn-off switching. Typically, two different types of capacitors are utilized in such switching circuits to reduce the switching frequency voltage. A relatively large storage capacitor is coupled to the voltage distribution bus which supplies power to the semiconductor switching devices. This large storage capacitor functions to provide low frequency current filtering. Smaller, fast switching capacitors are located in as close proximity as possible to the semiconductor switching devices and function to filter high amplitude transient currents which occur during the switching process. The smaller faster switching capacitors are characterized by high current handling capacity and typically are either coupled directly to the DC voltage power bus or form a part of various snubber circuits which are coupled to the semiconductor switching devices and which snubber circuits and techniques are well known to those skilled in the art. The construction and assembly of these typical circuits are time consuming, labor intensive and generally employ point-to-point wiring and high inductance capacitors which tends to present higher than desired impedances at the frequencies of interest.
It is desirable therefore to reduce the time and effort required to assemble and interconnect high frequency switching power semiconductor devices and current filtering and voltage transient suppression devices.
It is a general aim of the present invention therefore to provide a packaging assembly which facilitates a low impedance interconnection between high frequency switching power semiconductor devices and low inductance capacitors and a DC voltage potential applied to and switched by the semiconductor devices.
It is a further aim of the present invention to provide a low inductance modular capacitor for use with the assembly of the present invention.
It is a yet further aim of the present invention to provide a low impedance interconnection assembly that is not susceptible to damage due to mechanical shock and vibration.